The present invention relates to light emitting diode (LED) modules, and more particularly to a method and LED module for retrofitting existing commercial and street name signs presently illuminated with fluorescent tube lighting.
Light emitting diodes (LEDs) have been widely used in many applications to replace conventional incandescent lamps, fluorescent lamps, neon tube lamps and fiber optic lights. LEDs consume much less electrical power, are far more reliable, and exhibit much longer lifetimes, than their conventional counterparts. As a result, LEDs have been configured to replace conventional light sources for many applications. For example, LED lamps have been developed to replace screw-in incandescent light bulbs for traffic signals (as shown in U.S. Pat. No. 6,036,336), and exit signs (as shown in U.S. Pat. Nos. 5,416,679, 5,459,955, 5,526,236, 5,688,042, 5,949,347). In each case, the LEDs arc mounted onto a lamp housing having a conventional threaded electrical connector that engages with the threaded socket connector in the traffic signal lamp or exit sign. Thus, retrofitting the traffic signal and exit signs simply involves unscrewing the conventional lamp and screwing in the LED lamp.
Retrofitting with LED lamps the vast numbers of backlit commercial and street name signs, which utilize fluorescent lighting, is more problematic. These signs typically include a housing containing one or more fluorescent tube lamps, and one or more translucent face plates (sidewalls) that are back-illuminated by the fluorescent lamp(s) (i.e. to form characters, designs, symbols, etc.). FIGS. 1A and 1B illustrate a conventional backlit street name sign, which includes a housing 1, a pair of fluorescent tube lamps 2 and a pair of opposing translucent face plates 3 that indicate a street name. Each of the fluorescent tube lamps 2 are connected to and suspended by a pair of electrical connectors 4, which are well known in the art. The face plates 3 are angled slightly downwardly for better viewing from below. FIGS. 2A and 2B illustrate a convention backlit commercial sign, where there is only a single translucent face plate 3 (which is not angled downwardly), and three fluorescent tube lamps 2 for illumination.
Replacing the short-lifespan fluorescent tube lamps in conventional backlit commercial and street name signs can be difficult, because such signs are typically elevated and inaccessible, disposed over roadways, and/or hard to open. What is worse is that there is no standard size for such signs, for the fluorescent tube lamps 2 used therein, and for the spacing between the electrical connectors 4. Thus, designing an LED lamp retrofit that fits a wide variety of such signs, that evenly and sufficiently illuminates such signs, and that is easy to install without the need for special tools, has been difficult. Adding to that difficulty is the fact that many such signs are suspended in a way that the sign rocks, vibrates and shakes in the wind.
There is a need for a versatile LED lamp design for retrofitting conventional backlit commercial and street name signs that is easy to install and fits in a variety of sign sizes and configurations.
The present invention solves the aforementioned problems by providing an LED lamp design and method for conveniently retrofitting conventional backlit signs.
The LED module of the present invention includes a first support member having a first mounting surface, a first plurality of LEDs mounted to the first mounting surface, first and second support arms attached to the first support member, a first mounting mechanism attached to the first support arm, and a second mounting mechanism attached to the second support arm. Each of the first and second mounting mechanisms include first and second scissor arms and a first screw. Each of the scissor arms have an upper portion, a lower portion and a mid portion therebetween, wherein the mid portions of the first and second scissor arms are rotatably connected together and each of the lower portions includes an engagement surface. The first screw is engaged with the first and second scissor arm upper portions for adjusting a distance therebetween and a separation distance between the engagement surfaces of the first and second scissor arm lower portions.
In another aspect of the present invention, a backlit sign includes a housing having first and second side walls with at least a portion of the first sidewall being translucent, a first support member disposed in the housing and having a first mounting surface facing the first sidewall, a first plurality of LEDs mounted to the first mounting surface for illuminating the first sidewall, first and second support arms attached to the first support member, a first mounting mechanism attached to the first support arm, and a second mounting mechanism attached to the second support arm. Each of the first and second mounting mechanisms include first and second scissor arms and a first screw. Each of the scissor arms have an upper portion, a lower portion and a mid portion therebetween, wherein the mid portions of the first and second scissor arms are rotatably connected together and each of the lower portions includes an engagement surface that is pressed against one of the first and second sidewalls to form a friction fit therewith. The first screw is engaged with the first and second scissor arm upper portions for adjusting a distance therebetween and a separation distance between the engagement surfaces of the first and second scissor arm lower portions to increase or decrease a force with which the engagement surfaces are pressed against the sidewalls.
Another aspect of the present invention is a method of retrofitting a backlit sign having a housing with first and second sidewalls, and a light source disposed inside a housing, wherein at least a portion of the first sidewall is translucent, the method including removing the light source from the housing, and inserting an LED module into the housing. The LED module includes a first support member disposed in the housing and having a first mounting surface, a first plurality of LEDs mounted to the first mounting surface for illuminating the first sidewall, first and second support arms attached to the first support member, a first mounting mechanism attached to the first support arm, and a second mounting mechanism attached to the second support arm. Each of the first and second mounting mechanisms include first and second scissor arms and a first screw. Each of the scissor arms have an upper portion, a lower portion and a mid portion therebetween, wherein the mid portions of the first and second scissor arms are rotatably connected together and each of the lower portions includes an engagement surface. The first screw is engaged with the first and second scissor arm upper portions for adjusting a distance therebetween and a separation distance between the engagement surfaces of the first and second scissor arm lower portions. The method also includes rotating the first screw to press the engagement surfaces against the first and second sidewalls to form a friction fit therewith for securing the LED module within the housing.
Other objects and features of the present invention will become apparent by a review of the specification, claims and appended figures.